Number glow tubes having transformer energizing circuits

ABSTRACT

Apparatus is provided for generating electrode voltage for a number tube utilizing a center-tapped transformer to transmit pulses to a number tube anode. The transformer primary is centertapped and supplied with opposing pulse potentials at the outer ends through non-linear resistors at a time corresponding to the appearance of voltage on a selected cathode electrode. A d.c. bias potential is connected to the tube anode to complement the pulse voltage of the transformer. The pulses are derived from a ring counter.

United States Patent [451' May 30, 1972 Drage [54] NUMBER GLOW TUBES HAVING TRANSFORMER ENERGIZING CIRCUITS [72] Inventor: James John Drage, Uxbridge, England [73] Assignee: Sumlock Anita Electronics Limited, Ux-

bridge, Middlesex, England [22] Filed: Nov. 9, 1970 [21] Appl. No.: 87,875

[30] Foreign Application Priority Data Nov. 13, 1969 Great Britain ..55,65l/69 [52] US. Cl ..3l5/84.6, 328/47, 328/125 [51] Int. Cl. ..H0lj 17/48 [58] Field ofSearch ..328/12l,l22,123,124,198,

[56] References Cited UNITED STATES PATENTS 2,594,357 4/1952 Seaman ..313/l09.5 X 3,183,404 5/1965 Kitz et a.l.... ..3l5/135 3,119,950 1/1964 Somlyody ..3l5/84.6 3,307,171 2/1967 Claessen ..3l5/84.6 X

Primary Examiner-John S. Heyman Attorney-Laurence R; Brown [5 7] ABSTRACT 12 Claims, 6 Drawing Figures Patented May 30, 1972 3,666,987

3 Sheets-Sheet 1 James 10 m Dra a Patented May 30, 1972 3 Sheets-Sheet 2 L5 COUNTER RING M J rd h i w VTM. I L e NUMBER GLOW TUBES HAVING TRANSFORMER ENERGIZING CIRCUI'IS This invention has reference to circuits for number-indicating tubes, and has particular, but not exclusive, reference to number tube circuits which are used in number-display apparatus in which the dynamic read-out system of operation is used to display in visual form the digit or digits stored in an associated device. An example of the use of such number tube circuits is the visual indication of the number of digit pulses stored in the stage of a register of a calculating machine.

The dynamic read-out system of operation enables the number of digit pulses in the respective stages of the register to be displayed in sequence on the corresponding number tubes. In the dynamic read-out system of operation the anodes of the number tubes and each stage of the register are pulses in cyclic sequence to cause non-destructive read-out of the group of digit pulses stored in each of the stages of the register into a circuit connected to all of the cathodes of the number tubes. The results of the read-out is indicated on the number tube in which the cathode and anode pulses are coincident. The repetition rate of the read-out pulses to each stage of the register is such that, due to the persistence effect of ocular vision, the number of digit pulses which are pulses into each of the number tubes will be indicated as an array of apparently stationery numerals.

The circuits previously used for generation of the cyclic sequential pulses to the anodes of the number tubes comprise a transistor switch circuit in each anode circuit respectively. The transistor circuits are operable to control the application of the anode voltage to the respective number tube anode.

The operation of the transistor switch circuits is controlled by the respective outputs of a timer circuit. An output of the timer circuit is used to synchronize the anode pulses with the cathode pulses. Such a previous circuit when used to generate successive anode pulses for number tubes of a standard type, has a continuous power rating of about 7 watts and this power rating is a significant fraction of the rating of any associated equipment powered from the same power source. If the associated equipment comprises circuits which include semiconductor elements, e.g. transistors, diodes, or semiconductor integrated circuits, the power rating of the number tube circuits previously used would constitute the largest single load on the power supply and would require potential at a high level instead of the low level of potential required by the associated equipment.

An object of this invention is to provide an improved circuit for number-indicating tubes.

A further object of this invention is to provide a circuit for number-indicating tubes which uses the dynamic read-out system of operation and which is/may be used in calculating machines.

According to the present invention there is provided an apparatus for generating an electrode voltage for a number tube the apparatus comprising a transformer having a centertapped primary winding, the center-tap of the primary winding being connected to a source of potential and the untapped ends of the primary winding being connected to pulse sources respectively which alternately emit pulses, and having a secondary winding, one end of the winding being adapted for connection to an electrode of a number tube and a non-linear resistor having one connection connected to the one end of the secondary winding and having the other end connected to a source of bias potential so as to prevent the voltage at the one end of the secondary winding from falling below a potential at or near the potential of the source of bias potential; whereby, when a pulse is emitted from one of the pulse sources and when potentials are applied to the sources of potential, a pulse of one polarity is generated in the secondary winding one one direction to provide a voltage as a pulse at the electrode of the number tube; and whereby, when a pulse is emitted from the other of the pulse sources and when potential are applied to the sources of potential, a pulse of the reverse polarity to the one polarity is generated in the secondary winding in the other direction to provide a voltage as a pulse in that other direction.

Further according to the invention there is provided an apparatus for generating an electrode voltage for a number tube the apparatus comprising a transformer having center-tapped primary and secondary windings the center taps of the primary and secondary winding being connected to a source or sources of potential, a non-linear resistor connected to the non-tapped end of one of the secondary windings and adapted for connection to an electrode of the number tube, a first switching means connected to the non-tapped end of one of the primary windings, a second switching means connected to the nontapped end of the other of the primary windings, and a source of cyclically-occuring pulses having two consecutive pulses connected to the inputs of the first and second switching means respectively;.whereby, when a pulse is applied to the input of the first switching means, a pulse of one polarity is generated in the one of the secondary windings to provide a voltage as a pulse at the electrode of the number tube and a pulse of a reverse polarity is generated in the other of the secondary windings, and whereby, when a pulse is applied to the input of the second switching means, a pulse of the one polarity is generated in the other of the secondary windings and a pulse of a reverse polarity is generated in the one of the secondary windings.

Further according to the invention there is provided an apparatus for generating an electrode voltage for a number tube, the apparatus comprising a transformer having a centertapped primary winding and a non-center-tapped secondary winding, the center tap of the primary winding being connec'ted to a source of direct-current potential, one end of the secondary winding being adapted for connection to the electrode of the number tube, a first non-linear resistor having one connection connected to one end of the secondary winding and having the other connection connected to a source of direct-current potential, a second non-linear register having one connection connectedto the end of the secondary winding and having the other connection connected to a source of direct-current potential, a first switching means connected to the non-tapped end of one of the primary windings, a second switching means connected to the non-tapped end of the other of the primary windings and a source of cyclically-occuring pulses having two consecutive pulses connected to the inputs of the first and second switching means respectively; whereby, when a pulse is applied to the input of one of the switching means, a pulse having the point of highest potential at the one end of the secondary winding is induced in the secondary winding to provide a voltage as a pulse at the electrode of the number tube; and whereby when a pulse is applied to the input of the other of the switching means, a pulse having the points of highest potential at the other end of the secondary winding is induced in the secondary winding.

Further according to the invention there is provided an apparatus for generating an electrode voltage for a number tube, the apparatus comprising a transformer having a centertapped primary winding and a non-center-tapped secondary winding, one end of the secondary winding being adapted for connection to an electrode of a number tube, a first non-linear resistor having one connection connected to the one end of the secondary winding and having the other connection connected to a source of direct-current potential, a second nonlinear resistor having one connection conneeted to the other end of the secondary winding and having the other connection connected to a source of direct-current potential, a source of cyclically-occuring pulses having a pair of outputs for trans mitting alternate pulses respectively and having outputs for transmitting two consecutive pulses of the cycle of pulses respectively, a third non-linear resistor having one connection connected to the non-tapped and of one of the primary windings and having the other connection connected to one of the outputs of alternate pulses, a. fourth non-linear resistor having one connection connected to the non-tapped end of the other of the primary windings and having the other connection connected to the other of the outputs of alternate pulses, and a switching means having the input connection connected to one of the outputs of two consecutive pulses and having the output connection connected to the center tap of the primary winding; whereby, when one of the two consecutive pulses is applied to the switching means and when one of the altematepulses is applied to one of the non-tapped ends of one of the primary windings, a pulse having the point of highest potential at one of the non-tapped ends of the secondary winding is induced in the secondary winding; and whereby, when the'other of the two consecutive pulses is applied to the switching means and when one of the alternate pulses is applied to the other of the non-tapped ends of the other of the primary windings, a pulse having the point of highest potential at the other of the non-tapped ends of the secondary winding is induced in the secondary winding.

The electrode voltage generated is preferably the anode voltage. One apparatus for generating an electrode voltage is preferably used to generate the electrode voltages consecutively applied to the electrodes of a pair of number tubes; the electrodes of the two number tubes are connected to the untapped ends of the secondary windings respectively so that the secondary circuit is electrically symmetrical.

Constructional embodiments made in accordance with the invention will now be described, by way of examples, with reference to the accompanying drawing wherein:

FIG. 1 shows a first embodiment of a circuit for number-indicating tubes;

FIG. 2 shows a graph to a base of elapsed time, the pulse waveforms at various points on the circuit in FIG. 1;

FIG. 3 shows a second embodiment of a circuit for numberindicating tubes;

FIG. 4 shows a graph to a base of elapsed time, the pulse waveforms at various points on the circuit shown in FIG. 3;

FIG. 5 shows a third embodiment of a circuit for number-indicating tubes; and 1 FIG. 6 shows a graph to a base of elapsed time, the pulse waveforms at various points on the circuit shown in FIG. 5.

FIG. 1 shows a first embodiment of a circuit for number-indicating tubes which includes a plurality of electrically-controlled digital display devices or number-indicating tubes 1 which are well known in the art. Each number-indicating tube 1 has a single control conductor or anode electrode and display conductors or cathode electrodes which are each shaped to form a different'digit' number. The space between the anode and cathodes may be filled with a rare gas, e.g.

neon, and a small quantity of mercury. A particular digit cathode is illuminated when a voltage pulse applied to the anode is applied at the same time as a complementary pulse is applied to the particular digit cathode. The cathodes of the number-indicating tubes 1 which are shaped to the same number are connected in parallel to the corresponding line of the 10 number lines 3. A cathode circuit (not shown) receives a train of digit pulses from a store device (not shown) and causes a pulse to be transmitted along that number line 3 connected to the cathode which is shaped to the digit corresponding to the number of digit pulses in the train of digit pulses.

The number-indicating tubes 1 are arranged in pairs (only one pair shown) and the anodes Al and A2 of the left hand and right hand of each pair of number-indicating tubes respectively are connected to non-linear resistors in the form of diodes D1 and D2 respectively. The cathodes of the diodes 'DI and D2 are connected to the anodes Al and A2 of the number-indicating tubes respectively. The anodes of thediodes D1 and D2 are connected to the non-tapped ends of the windings 7a and 7b respectively of the center-tapped secondary winding 7 of a transformer 9. The center tap of the secondary winding 7 is connected to a potential of volts d.c.. The primary winding 11 of the transformer 9 is centertapped and connected to a potential of 15 volts d.c.. Each of the secondary windings 7a and 7b have 10 times the number of windings that are wound on each of the primary windings 11a and 11b. The untapped end of the winding 11a is connected to the collector of an N-P-N transistor circuit 13 which forms a switching circuit. The input of the switching circuit 13 is connected to an input line T1 of a source of cyclically-generated voltage pulses such as a ring counter 15. The untapped end of the winding 11b is connected to the collector of an N-P-N transistor circuit 17 which forms a switching circuit. The input of the switching circuit 17 is connected to an output line T2 of the ring counter 15.

The circuit for number-indicating tubes shown in FIG. 1 operates as follows:

The ring counter 15 generates a cyclically-repeated sequence of pulses on the output lines T1, T2, T3 and so on which are coincident with cathode pulses on the number line 3 from the cathode circuit (not shown). The pulses T1, T2, and T3 are shown in FIGS. 2 (a), 2 (b) and 2 (c) respectively.

When the positive-going output T1 is applied to the input of the non-conducting transistor circuit 13, the transistor conducts and the positive-going pulse T1 is transmitted into the primary winding 11a which induces a negative-going voltage pulse in the primary winding 11b and the secondary winding 7b and induces a positive-going voltage pulse of about 10 times the amplitude of the pulse T1 in the secondary winding 70. The voltage pulse induced in the secondary winding 7a passes through the diode D1 and provides an anode voltage coincident with a pulse on one of the number lines 3 so that a number is displayed by the left-hand number-indicating tube for the duration of the pulse Tl.

Similarly, when the positive-going pulse T2 is applied to the input of the non-conducting switch circuit 17, the transistor conducts and the positive-going pulse T2 is transmitted into the primary winding 11b to induce a negative-going pulse in the primary winding 11a and the secondary winding 7:: and to induce a positive-going pulse of about 10 times the amplitude of the pulse T2 in the secondary winding 7b. The voltage induced in the secondary winding 7b passes through the diode D2 and provides an anode voltage coincident with a pulse on one of the number lines 3 so that a number is displayed by the right-hand number-indicating tube for the duration of the pulse T2.

The waveform of the secondary winding 7a during the pulses T1 and T2 is shown in FIG. 2 (d) and the waveform of the secondary winding 7b during the the FIG. 2 (e).

The FIG. 2 (f) shows the magnetizing current drawn by the transformer 9 and shows that, as a result of using a centertapped transfonner, the waveform of the magnetizing current is coincident with the duration of the pulses T1 and T2.

The circuit has the following advantages:

1. The circuit described has an even higher efiiciency than a single-winding transformer circuit. The losses associated with a single transformer are reduced because the resister-capacitor circuit used to control the decay of magnetizing current in the single-winding transformer are unnecessary in a centertapped transformer. Typically, the circuit described, when used with 10 number-indicating tubes, has a continuous power rating of about 2 watts instead of the usual continuous power rating of about 7 watts.

2. The circuit makes it possible to operate number-indicating tubes from a battery source.

3. If the pulse inputs to the pairs of switching circuits are consecutive, the intervals between the operation of the number-indicating circuits is unimportant so that the numberindicating circuit is independent of frequency.

4. The anode voltage pulse can be adjusted to any voltage above the maintainance voltage of the number-indicating tube in the positive direction and there is no voltage limit in the negative direction.

5. A further circuit economy can be made by designing the resistance of the transformer secondary windings 7a and 7b to each be of such a value that the winding resistance can be used as a current-stabilizing resistor for the anode current of the conducting number-indicating tube.

pulses T1 and T2 is shown in 6. The power circuits are simplified in that the high-voltage outputs of 90V or 180V are no longer needed to supply the anode voltage.

FIG. 3 shows a second embodiment of a circuit for numberindicating tubes. The difference between the circuit shown in FIG. 3 and the circuit shown in FIG. 1 lies in the secondary circuit of the transformer 9. Since the circuits are similar, identical components will carry the same reference numeral and components altered in construction or function in the secondary circuit will carry their old reference numeral with the addition of a dash. The secondary winding 7 of the transformer 9' is not center-tapped and comprises a winding equal in number of turns to one of the winding 7a or 7b of the transformer 9 so that the secondary winding 7' has times the number of windings of either of the primary windings 110 or 1 1b.

The secondary bias voltage of volts d.c. is applied through the diodes D1 and D2 whose cathodes are connected to the ends of the secondary winding 7' respectively.

The circuit shown in FIG. 3 operates in a similar manner to the operation of the circuit shown in FIG. 1 previously described. When the ring counter 15 emits a pulse T1, shown in FIG. 4 (a), which is applied to the base of the transistor circuit 13, a pulse is generated in the primary winding 110 which induces in the secondary winding 7 a voltage pulse A1 of 10 times its own amplitude. The pulse Al is shown in FIG. 4 (d). The highest potential of the voltage pulse A1 occurs at the cathode connection D1 so that the anode of the left-hand number-indicating tube 1 receives the positive voltage pulse A1 and so that the D1 is reverse biased while the voltage pulse Al is present. The diode D2 holds the other end of the secondary winding 7' near to the secondary bias potential of 15 volts do. so that the anode of the right-hand number tube 1 is not raised to the positive striking voltage but the minimum rise in positive voltage will be needed to reach this striking voltage so as to cause the number-indicating tube to conduct. Similarly, when a pulse T2 shown in FIG. 4 (b) is applied to the base of the transistor circuit 17, a voltage pulse A2 is applied to the anode of the right-hand number-indicating tube 1 and the diode D1 holds the anode of the left-hand number-indicating tube 1 near to the secondary bias potential.

The circuit shown in FIG. 3 has the following advantages:

a. The advantages 1, 2, 3, 4, 5, 7 and 8 of the circuit shown in FIG. 1; and

b. The advantages over the circuit shown in FIG. 1 in that the transformer requires no secondary center-tap and the secondary winding requires only half of the number of turns previously required.

FIG. 5 shows a third embodiment of a circuit for number-indicating tubes. The difference between the circuit shown in FIG. 5 and the circuit shown in FIG. 3 is in the connections to the primary circuit 1 l of the transformer 9. The signals on the output lines of the ring counter 15 have been altered to reduce the number of output lines required. The output line 0 and the output line E alternately transmit the unaltered pulses generated by the ring counter 15' as shown in FIG. 6 (a) and 6 (b) respectively and the other output lines each transmit two consecutive pulses respectively as shown for line (T1 T2) and line (T3 +T4) in FIG. 6 (c) and 6 (d) respectively, The output line E is connected through a forward-biassed diode D3 to the un-tapped end of the primary winding 11a and the output-line 0 is connected through forward-biassed diode D4 to the untapped end of the primary winding .1 1b. The center tap of the primary winding is connected to the collector of N- P-N transistor circuit which acts as a switching circuit. The base of the transistor circuit 20 is connected to the (T1 +T2) line of the ring counter 15'.

The circuit shown in FIG. 5 operates as follows:

When the line (Tl T2) transmits the pulse T1 to the transistor circuit 20, the line E is at zero volts and the line 0 has the positive pulse Tl applied to it.

The transistor circuit 20 conducts when the pulse T1 is applied to it, so that the center-tap is connected to a zero potential and so that zero potential difference-appears across the primary winding 11a and that a positive potential difierence appears as a pulse across the primary winding 11b. The pulse in the primary winding 11b induces in the secondary winding 7' a voltage pulse whose point of highest potential is situated at the cathode of the diode D1 so that the circuit operates as similarly described for the circuit shown in FIG. 3. Similarly, when the pulse T2 is applied to the transistor circuit 20, a voltage pulse is induced in the secondary winding 7 and has the point of highest potential situated at the cathode of the diode D2. The circuit shown in FIG. 3 has the following advantages over the circuit shown in FIG. 3:

1. One of the transistor circuits is replaced by two diodes so I that the circuit is cheapened and made more economical.

2. The output lines of the ring counter are reduced so that the circuit is made more economical and lead-limited circuit elements can be more readily used to construct the circuit.

3. The replacement of the direct-current potential at the center-tap of the primary winding by a pulse circuit may result in a further reduction in the power rating for the circuit shown in FIG. 5.

It is possible to reverse the polarities of the diodes and change the transistors to P-N-P types so that the circuits described can be operated with negative potentials and negative going pulse trains.

The circuits described can be duplicated to supply anode potentials to any number of number-indicating tubes.

What we claim is:

1. Apparatus for displaying numbers on at least two character display cathode glow tubes having an anode and a plurality of cathodes each in the form of a character indication which will glow upon exceeding a d. c. threshold potential between the anode and one or more cathodes, comprising in combination, a transformer having a center-tapped primary winding and a secondary winding, circuit means connecting the opposite ends of said secondary winding to the anodes of said two tubes to thereby provide for excitation of the respective anodes above the threshold potential in a polarity to cause a selected character to glow in the respective tubes in response to opposite polarities of excitation, and switching means coupled to opposite ends of said center-tapped primary winding to produce a pulse at one end only at a time to thereby cause a respective one of said anodes to receive a voltage above said threshold potential.

2. Apparatus as defined in claim 1, wherein said secondary winding is center-tapped.

3. Apparatus as defined in claim 1, wherein a positive d. c. voltage source is connected to each of said two anodes.

4. Apparatus as defined in claim 3 including a non-linear resistor coupling each anode to said d. c. voltage.

5. Apparatus as defined in claim 4, wherein the secondary winding is center-tapped, the d. c. voltage is applied to the center-tap of the secondary winding and the non-linear resistors are rectifiers coupling the respective anodes to the opposite ends of said secondary winding.

6. Apparatus as defined in claim 4, wherein the non-linear resistors are diodes and the transformer secondary winding is untapped and coupled to the respective anodes, and a circuit couples each diodes to a respective anode and said (1. c. source.

7. Apparatus as defined in claim 1, wherein said switching means comprises counter means sequentially producing pulses at opposite ends of said primary winding.

8. Apparatus as defined in claim 7 including a transistor circuit coupled between the counter means and the primary winding center-tap.

9. Apparatus as defined in claim 7 including two transistor circuits respectively coupled from the opposite ends of the primary winding to said counter means.

10. Apparatus as defined in claim 1, wherein the plurality of tubes each have similar characters including circuit means connecting together the similar characters of each of the tubes. 1

7 8 11. Apparatus as defined in claim 10, wherein said transformer primary windiny. switching means comprises counter means providing a 12- Apparatus as defined in claim 11 including a single cursequcnce of successive pulses, and including a plurality of rem drivel" circuit coupled Said count means m h pairs of said tubes each provided with said transformer and a ccmermp ofcach transfomel' to Pmvide the p circuit coupling the successive pulses to different ends of said 

1. Apparatus for displaying numbers on at least two character display cathode glow tubes having an anode and a plurality of cathodes each in the form of a character indication which will glow upon exceeding a d. c. threshold potential between the anode and one or more cathodes, comprising in combination, a transformer having a center-tapped primary winding and a secondary winding, circuit means connecting the opposite ends of said secondary winding to the anodes of said two tubes to thereby provide for excitation of the respective anodes above the threshold potential in a polarity to cause a selected character to glow in the respective tubes in response to opposite polarities of excitation, and switching means coupled to opposite ends of said center-tapped primary winding to produce a pulse at one end only at a time to thereby cause a respective one of said anodes to receive a voltage above said threshold potential.
 2. Apparatus as defined in claim 1, wherein said secondary winding is center-tapped.
 3. Apparatus as defined in claim 1, wherein a positive d. c. voltage source is connected to each of said two anodes.
 4. Apparatus as defined in claim 3 including a non-linear resistor coupling each anode to said d. c. voltage.
 5. Apparatus as defined in claim 4, wherein the secondary winding is center-tapped, the d. c. voltage is applied to the center-tap of the secondary winding and the non-linear resistors are rectifiers coupling the respective anodes to the opposite ends of said secondary winding.
 6. Apparatus as defined in claim 4, wherein the non-linear resistors are diodes and the transformer secondary winding is untapped and coupled to the respective anodes, and a circuit couples each diodes to a respective anode and said d. c. source.
 7. Apparatus as defined in claim 1, wherein said switching means comprises counter means sequentially producing pulses at opposite ends of said primary winding.
 8. Apparatus as defined in claim 7 including a transistor circuit coupled between the counter means and the primary winding center-tap.
 9. Apparatus as defined in claim 7 including two transistor circuits respectively coupled from the opposite ends of the primary winding to said counter means.
 10. Apparatus as defined in claim 1, wherein the plurality of tubes each have similar characters including circuit means connecting together the similar characters of each of the tubes.
 11. Apparatus as defined in claim 10, wherein said switching means comprises counter means providing a sequence of successive pulses, and including a plurality of pairs of said tubes each provided with said transformer and a circuit coupling the successive pulses to different ends of said transformer primary windings.
 12. Apparatus as defined in claim 11 including a single current driver circuit coupled from said counter means to the center-tap of each transformer to provide the pulses. 